Well i would suggest, that to use a personal trainer and pay him for his services, would possibly be part of a fantasy, most personal trainers can get sex very easily, even from there paying clients, Also, would this would show your level of commitment, if you cant separate sex from working , save it for the locker room, having a personal trainer, that you also have sex with would blurr the boundries and your less likely to take notice of them when they are 'putting you through your paces' for your own benefit. Why not find a boyfriend who is personal trainer,